Complete the square to solve for $x$. $x^{2}+18x+81 = 0$
Solution: The left side of the equation is already a perfect square trinomial. The coefficient of our $x$ term is $18$ , half of it is $9$ , and squaring it gives us ${81}$ , our constant term. Thus, we can rewrite the left side of the equation as a squared term. $( x + 9 )^2 = 0$ Take the square root of both sides. $x + 9 = 0$ Isolate $x$ to find the solution(s). The solution is: $x = -9$ We already found the completed square: $( x + 9 )^2 = 0$